KANSAS CITY, Mo. – And afterwards, they sang. Now, nobody on the Colts figures to earn a spot on “The Voice,” but after working over the Kansas City Chiefs, 23-7, after playing their best top-to-bottom, soup-to-nuts game in months, the Colts sang along with Bob Marley’s “Three Little Birds.”

Yeh, mon.

“Don’t worry ‘about a thing…cuz every little thing, gonna be all right…’’

First it was an Anthony Castonzo. Then it was a Castonzo-Gosder Cherilus duet. Then the whole locker room chimed in.

“Rise up this mornin’/Smiled with the risin’ sun/Three little birds/By my doorstep/Singin’ sweet songs/Of melodies pure and true/Saying, this is my message to you-oo-oo…”

Yes, every little thing, gonna be all right.

Because this, boys and girls, was a conversation changer. A week ago, two weeks ago, the conversation centered around how quickly the wounded and inconsistent Colts would be dispatched from the postseason. The conversation now is suffused with something resembling hope, the talk centering now on how far the suddenly resurgent Colts might go in the playoffs.

All they did Sunday at Arrowhead was produce their best start-to-finish, all-around performance since an early-season throttling of the San Francisco 49ers at Candlestick Park.

All they did was resurrect the notion that yes, they could roll into the postseason and make some noise. If they could come into Arrowhead, into the din and the brutish cold, and dominate an 11-win team like this, why not do something special in January?

“This gives us a lot of confidence because we know that eventually we’ll probably have to go on the road in the playoffs,” said guard Mike McGlynn, whose patchwork offensive line made Tamba Hali and the Chiefs pass rush disappear into the frigid air. “This was a great steppingstone for us.”

This was the team we saw through that 6-2 first half of the season. This was the team that beat San Francisco, beat Seattle, beat Denver. Some of us thought they’d lost their edge irreversibly when Reggie Wayne went down with his injury. But the Colts, playing a grown-man type of game here, resurrected the wobbly notion that maybe, just maybe, they can do something in the playoffs.

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On a nasty, cold, harsh day — “a summer’s day in Saskatchewan,” former Canadian Football Leaguer Jerrell Freeman joked — the Colts sent a message to the rest of the league. They may have lost five offensive starters to season-ending injuries, but they’re still a 10-win team with a chance to equal last year’s total of 11 victories, still a player to consider come the postseason.

They’ve found their mojo, their momentum, their sense of self. The defense was brilliant, forcing four turnovers, limiting Kansas City — the same K.C. offense that scored 101 points the last two weeks — to seven early points and just 287 total yards, including 1-of-8 on third down conversions. The offense was solid and efficient, breaking two big plays, courtesy of Donald Brown, moving the sticks, Super-Gluing Alex Smith and his offense to the heated benches.

And the offensive line?

Let’s talk about the offensive line. They’ve used a league-high seven offensive lines this season, including five different ones the last five weeks. And yet, they played a nearly perfect game against the sack-happy Chiefs, just as they played a nearly spotless game against J.J. Watt, Antonio Smith and the Houston Texans.

Everybody has taken shots at the O-line this year, myself included, and the statistics suggest the criticism has been largely justified. But give them credit. They haven’t crawled into the fetal position, haven’t taken refuge in self-pity. They’ve just kept grinding. And so there they were Sunday afternoon, starting Xavier Nixon at right guard, a guy who had never played guard in his life until he played it last week against Houston. McGlynn was back at guard. The much-ripped Samson Satele was at center.

I told Castonzo, “I don’t think I heard Tamba Hali’s name all day.”

(Castonzo, the left tackle, was lined up against the Pro Bowl right defensive end, all game).

“Oh, he got me a few times,” Castonzo conceded. “But those couple of times, Andrew (Luck) got the ball out in time. But it was a strong game from the whole line. I don’t know why we’re coming together; I wish I knew. But we’ve just kept our heads down and kept working. It’s great to put together two wins in a row like this. We just beat a really good playoff team; now we’ve just got to keep it rolling for one more week and then into the playoffs.”

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A week ago, Kansas City’s Jamaal Charles went nuts and scored five touchdowns against the Oakland Raiders. This week, the Colts mixed up their coverages and consistently kept Charles at bay except for an early first-quarter touchdown run. He finished with 106 rushing yards — 31 on the TD run — but caught only five passes for 38 yards.

“It was ‘Where’s Waldo?’ all week for us,” Antoine Bethea said of Charles, the Chiefs only true breakaway threat. “He’s a great, great player. He leads that team in rushing and receiving. We knew he was their go-to guy and if we could take him out of the game, it would be tough for their offense to get going.”

Ten points allowed in two weeks.

The defense, which is mostly healthy now except for lineman Ricky Jean Francois, has come alive. The secondary and linebackers plastered themselves to Kansas City’s receivers all afternoon, playing press coverage, daring them to beat them. How often did you see a receiver with separation? Rarely. Very rarely. Defense will take this team as far as it can go. Did in 2006.

“We’re starting to play the way we played earlier this year,” Freeman said. “We’ve just got to keep this roll going.”

With that, the locker room filled again with the happy noise of grown men singing a joyful reggae anthem.

“Don’t worry/’Bout a thing/Cuz every little thing/Gonna be all right.’’

And you know what? After this, it just might.

Bob Kravitz is a columnist for The Indianapolis Star. Contact him via email at bob.kravitz@indystar.com. Follow him on Twitter: @BKravitz.